The Cancer Genome Atlas (TCGA) is a comprehensive and coordinated effort to accelerate our understanding of the molecular basis of cancer through the application of genome analysis technologies, including large-scale genome sequencing. The overarching goal of The Cancer Genome Atlas (TCGA) is to improve our ability to diagnose, treat and prevent cancer. To achieve this goal in a scientifically rigorous manner, the National Cancer Institute and the National Human Genome Research Institute used a phased-in strategy to launch TCGA. A pilot project developed and tested the research framework needed to systematically explore the entire spectrum of genomic changes involved in human cancers. Based on the extraordinary sets of multidimensional data generated by the pilot, TCGA has moved from a pilot to a full program to study more than 20 types of cancer.